AR-15 Lower Parts Kit

AR-15 versus AR-10 Lower Parts Kit Differences

Seldom has a rifle dominated the scene for such a long time than the AR-15. Whether it is house protection or hunting, this rifle seems to be the perennial favorite. The AR-10, the AR-15’s predecessor, is also an equally good rifle, albeit with fewer features than the later.

The AR-10 is also magazine fed and modular, which means that it is also to a considerable extent, customizable, just like the AR-15. In fact, you can build an AR-10 with 80% lower receiver quite easily.

A full power .308 caliber round feature of the AR-10 is one of the key differentiating factors from the AR-15. Another significant difference between the two is the fact that the AR-15 is a standardized platform.

With AR-10 things are a bit different. There is no design standardization, and various companies offer their own versions of AR-10. Two of the common versions of complete rifles going around in the market are the Armalite series and the DPMS series. The DPMS series offers a slight advantage over the Armalite in the sense that most of its parts are interchangeable with that of other brands of rifles.

Lower Parts Kit

The size difference between these two rifles means that only a small percentage of parts are interchangeable, particularly concerning the lower receivers. Some parts that can be swapped include the trigger and trigger springs.

Parts that cannot be interchanged include the magazine catch, pistol grips, bolt catch and takedown pins. These days several kits suppliers though are utilizing the latest machining technology, continually adding to the parts that can be swapped between these two rifles, especially in the case of lower receivers, since nothing can be done to the size of ar-15 upper receivers.

One of the best ways for ensuring a more extensive choice of parts for your AR-10 80% lower receiver is to go in for a jig that is specifically matched or the platform. This is again unlike the case with AR-15s, which would work well with literally any jig. However, in this case, you will need to ensure that you have the right jig with the other necessary tools before you start building your gun.

Pistol Grips

Most of the pistol grips that are available for the AR-10 cannot be swapped with the AR-15. This is once again because of the slight difference in the sizes of the two. Stripped pistol grips, however, seem to be favorite when it comes to both AR-10 and AR-15 lower parts nowadays. Since accuracy and precision are so dependent on the right grip, there are several types of grips doing the market these days.


There is a significant height difference between the magazine used in AR-10 and AR-15. The AR-15 build is much more compact and therefore the difference. Interestingly while AR-15 may be smaller, its magazine, in fact, contains one rounder than the AR-10.

The larger size of the magazine of AR-10 also means they can hold taller sized cartridges. In fact, all that you need to do is to walk into a gun shop and lift a box of .308 cartridges and compare the weight with a box of .223 ones and you will feel the difference.

Remember, the AR-10 was originally designed for combat purposes and that explains the taller and more powerful ammunition than AR-15s, which are mostly used for recreation purposes nowadays.

Magazine Catch

Another part which will be different for the two rifles is the magazine catch. It will be slightly smaller in size in the case of the AR-15. Even among the different manufacturers of AR-10, there would be differences in the size of the magazine catch. You just need to check for the range of 80% lower build for AR-10s available in the market to find out the difference.

Take Down Pins

The difference in sizes between the two rifles is once again the reason for the fact that their takedown pins cannot be swapped. The takedown pins in the case of AR-10 are 9/32″.

Those designed for the AR-15 typically fit other .223 rifles, but not .308 caliber rifles like the AR-10. Whichever may be the case, it is always preferred to go in for the knurled knob, for this will ensure that you can remove the pins without the help of any tools.

Bolt Catch

The humble bolt catch does not quite often receive the kind of attention it warrants, given the key role that it performs. In this case, too, the 1/16 “socket head featuring bolt catch screw in an AR-10 is bigger in size than the ones that fit an AR-15.

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